Why worry about sea level rise now?

If the Greenland and Antarctic ice sheets lose too much ice they will pass a ‘tipping point’ [1,2,3,4,5]. This happens when the area of ice lost becomes so large that it is impossible to stop the rest of the ice sheet from melting too [3,6].

The Greenland ice sheet is heading towards this point because as it melts, it moves to lower areas of land. Because air is warmer on lower land the rate of melting increases [5].

Once these tipping points are crossed, changes are likely to be irreversible [3] for thousands of years [7,8,9]. If the Greenland and western Antarctic ice sheets cross their tipping points, we have to expect several metres of sea level rise in the next few hundred years [8]. Completely melted, the Greenland ice sheet alone would contribute 7 metres [3,4,5,8,10]!